// SPDX-License-Identifier: GPL-2.0 /* * prepare to run common code * * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE */ /* cpu_feature_enabled() cannot be used this early */ #define USE_EARLY_PGTABLE_L5 #include <linux/init.h> #include <linux/linkage.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/percpu.h> #include <linux/start_kernel.h> #include <linux/io.h> #include <linux/memblock.h> #include <linux/cc_platform.h> #include <linux/pgtable.h> #include <asm/asm.h> #include <asm/page_64.h> #include <asm/processor.h> #include <asm/proto.h> #include <asm/smp.h> #include <asm/setup.h> #include <asm/desc.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/kdebug.h> #include <asm/e820/api.h> #include <asm/bios_ebda.h> #include <asm/bootparam_utils.h> #include <asm/microcode.h> #include <asm/kasan.h> #include <asm/fixmap.h> #include <asm/realmode.h> #include <asm/extable.h> #include <asm/trapnr.h> #include <asm/sev.h> #include <asm/tdx.h> #include <asm/init.h> /* * Manage page tables very early on. */ extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; unsigned int __initdata next_early_pgt; SYM_PIC_ALIAS(next_early_pgt); pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); unsigned int __pgtable_l5_enabled __ro_after_init; unsigned int pgdir_shift __ro_after_init = 39; EXPORT_SYMBOL(pgdir_shift); unsigned int ptrs_per_p4d __ro_after_init = 1; EXPORT_SYMBOL(ptrs_per_p4d); unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4; EXPORT_SYMBOL(page_offset_base); unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4; EXPORT_SYMBOL(vmalloc_base); unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4; EXPORT_SYMBOL(vmemmap_base); /* Wipe all early page tables except for the kernel symbol map */ static void __init reset_early_page_tables(void) { memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1)); next_early_pgt = 0; write_cr3(__sme_pa_nodebug(early_top_pgt)); } /* Create a new PMD entry */ bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd) { unsigned long physaddr = address - __PAGE_OFFSET; pgdval_t pgd, *pgd_p; p4dval_t p4d, *p4d_p; pudval_t pud, *pud_p; pmdval_t *pmd_p; /* Invalid address or early pgt is done ? */ if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) return false; again: pgd_p = &early_top_pgt[pgd_index(address)].pgd; pgd = *pgd_p; /* * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is * critical -- __PAGE_OFFSET would point us back into the dynamic * range and we might end up looping forever... */ if (!pgtable_l5_enabled()) p4d_p = pgd_p; else if (pgd) p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++]; memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D); *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } p4d_p += p4d_index(address); p4d = *p4d_p; if (p4d) pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } pud_p += pud_index(address); pud = *pud_p; if (pud) pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } pmd_p[pmd_index(address)] = pmd; return true; } static bool __init early_make_pgtable(unsigned long address) { unsigned long physaddr = address - __PAGE_OFFSET; pmdval_t pmd; pmd = (physaddr & PMD_MASK) + early_pmd_flags; return __early_make_pgtable(address, pmd); } void __init do_early_exception(struct pt_regs *regs, int trapnr) { if (trapnr == X86_TRAP_PF && early_make_pgtable(native_read_cr2())) return; if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) && trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs)) return; if (trapnr == X86_TRAP_VE && tdx_early_handle_ve(regs)) return; early_fixup_exception(regs, trapnr); } /* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ void __init clear_bss(void) { memset(__bss_start, 0, (unsigned long) __bss_stop - (unsigned long) __bss_start); memset(__brk_base, 0, (unsigned long) __brk_limit - (unsigned long) __brk_base); } static unsigned long get_cmd_line_ptr(void) { unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; return cmd_line_ptr; } static void __init copy_bootdata(char *real_mode_data) { char * command_line; unsigned long cmd_line_ptr; /* * If SME is active, this will create decrypted mappings of the * boot data in advance of the copy operations. */ sme_map_bootdata(real_mode_data); memcpy(&boot_params, real_mode_data, sizeof(boot_params)); sanitize_boot_params(&boot_params); cmd_line_ptr = get_cmd_line_ptr(); if (cmd_line_ptr) { command_line = __va(cmd_line_ptr); memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); } /* * The old boot data is no longer needed and won't be reserved, * freeing up that memory for use by the system. If SME is active, * we need to remove the mappings that were created so that the * memory doesn't remain mapped as decrypted. */ sme_unmap_bootdata(real_mode_data); } asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode_data) { /* * Build-time sanity checks on the kernel image and module * area mappings. (these are purely build-time and produce no code) */ BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); cr4_init_shadow(); /* Kill off the identity-map trampoline */ reset_early_page_tables(); if (pgtable_l5_enabled()) { page_offset_base = __PAGE_OFFSET_BASE_L5; vmalloc_base = __VMALLOC_BASE_L5; vmemmap_base = __VMEMMAP_BASE_L5; } clear_bss(); /* * This needs to happen *before* kasan_early_init() because latter maps stuff * into that page. */ clear_page(init_top_pgt); /* * SME support may update early_pmd_flags to include the memory * encryption mask, so it needs to be called before anything * that may generate a page fault. */ sme_early_init(); kasan_early_init(); /* * Flush global TLB entries which could be left over from the trampoline page * table. * * This needs to happen *after* kasan_early_init() as KASAN-enabled .configs * instrument native_write_cr4() so KASAN must be initialized for that * instrumentation to work. */ __native_tlb_flush_global(this_cpu_read(cpu_tlbstate.cr4)); idt_setup_early_handler(); /* Needed before cc_platform_has() can be used for TDX */ tdx_early_init(); copy_bootdata(__va(real_mode_data)); /* * Load microcode early on BSP. */ load_ucode_bsp(); /* set init_top_pgt kernel high mapping*/ init_top_pgt[511] = early_top_pgt[511]; x86_64_start_reservations(real_mode_data); } void __init __noreturn x86_64_start_reservations(char *real_mode_data) { /* version is always not zero if it is copied */ if (!boot_params.hdr.version) copy_bootdata(__va(real_mode_data)); x86_early_init_platform_quirks(); switch (boot_params.hdr.hardware_subarch) { case X86_SUBARCH_INTEL_MID: x86_intel_mid_early_setup(); break; default: break; } start_kernel(); } void early_setup_idt(void) { void *handler = NULL; if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { setup_ghcb(); handler = vc_boot_ghcb; } startup_64_load_idt(handler); }